[PATCH 0/2] b4: sparse-checkout related fixes

[PATCH 0/2] b4: sparse-checkout related fixes

[Michael S. Tsirkin]

I encountered shazam test failures, diagnozing them I realized
b4 misuses the sparse-checkout command.
This patchset cleans this up.
Pls review, thanks!

Michael S. Tsirkin (2):
  test_shazam: clean worktree before git am
  ez: cleanup sparse-checkout usage

 src/b4/__init__.py | 6 +++---
 src/b4/ez.py       | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

-- 
MST

[PATCH 1/2] test_shazam: clean worktree before git am

[Michael S. Tsirkin]

I see the following failures on master (as of commit 965071ee174d):

- test_shazam[shazam-git1-just-series-shazamargs1-compareargs1-shazam-git1-just-series-defaults-b4cfg1] FAILED
Error: "fatal: Dirty index: cannot apply patches (dirty: file1.txt file2.txt lipsum.txt)"

- test_shazam[shazam-git1-just-series-shazamargs2-compareargs2-shazam-git1-just-series-merged-b4cfg2] FAILED
Error: "fatal: Dirty index: cannot apply patches (dirty: file1.txt file2.txt lipsum.txt)"

Both tests fail because git am can't apply patches with a dirty index.

Specifically, the worktree is created with `git worktree add --detach --no-checkout`,
to save time checking out files to the working directory.
However, this means all files then appear as deleted in the index.

The test attempts to solve this by a combination of
"git sparse-checkout init" followed by "git checkout".
However, "git sparse-checkout init" does not actually create an empty
sparse checkout cone and additionally "git checkout" by default does not
update the index - it only updates the worktree from the index.

As a result, when "git am" tries to apply patches, it fails with "Dirty
index: cannot apply patches" because the index contains staged changes
(the "deleted" entries).

To fix, replace "git sparse-checkout init" with "git sparse-checkout
set"  - with no patterns, this actually creates an empty sparse checkout -
followed by "git checkout -f" to update the index to match HEAD,
clearing the staged deletions.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 src/b4/__init__.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/b4/__init__.py b/src/b4/__init__.py
index 142da25..31c7fa4 100644
--- a/src/b4/__init__.py
+++ b/src/b4/__init__.py
@@ -4501,12 +4501,12 @@ def git_fetch_am_into_repo(gitdir: Optional[str], ambytes: bytes, at_base: str =
 
     with git_temp_worktree(topdir, at_base) as gwt:
         logger.info('Magic: Preparing a sparse worktree')
-        ecode, out = git_run_command(gwt, ['sparse-checkout', 'init'], logstderr=True)
+        ecode, out = git_run_command(gwt, ['sparse-checkout', 'set'], logstderr=True)
         if ecode > 0:
-            logger.critical('Error running sparse-checkout init')
+            logger.critical('Error running sparse-checkout set')
             logger.critical(out)
             raise RuntimeError
-        ecode, out = git_run_command(gwt, ['checkout'], logstderr=True)
+        ecode, out = git_run_command(gwt, ['checkout', '-f'], logstderr=True)
         if ecode > 0:
             logger.critical('Error running checkout into sparse workdir')
             logger.critical(out)
-- 
MST

[PATCH 2/2] ez: cleanup sparse-checkout usage

[Michael S. Tsirkin]

Similarly to the previus patch, b4 ez uses sparse-checkout incorrectly:
- it does not want any files but it uses "init" which
  actually gives some files (the ones in the root)
- it runs checkout but it's pointless - index is left dirty,
  and it only happens to work because cherry-pick works
  with a dirty index (unlike e.g. am).

To fix, switch to sparse-checkout set to get an empty cone +
checkout -f to update the index.

We could actually skip checkout completely but it seems better
not to rely on the quirk of cherry-pick that allows it to
work with a dirty index, and an empty index is quick to update.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 src/b4/ez.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/b4/ez.py b/src/b4/ez.py
index 26772b4..4510be2 100644
--- a/src/b4/ez.py
+++ b/src/b4/ez.py
@@ -2386,12 +2386,12 @@ def reroll(mybranch: str, tag_msg: str, msgid: str, tagprefix: str = SENT_TAG_PR
                 base_commit, start_commit, end_commit = get_series_range(usebranch=mybranch)
                 with b4.git_temp_worktree(topdir, base_commit) as gwt:
                     logger.debug('Preparing a sparse worktree')
-                    ecode, out = b4.git_run_command(gwt, ['sparse-checkout', 'init'], logstderr=True)
+                    ecode, out = b4.git_run_command(gwt, ['sparse-checkout', 'set'], logstderr=True)
                     if ecode > 0:
-                        logger.critical('Error running sparse-checkout init')
+                        logger.critical('Error running sparse-checkout set')
                         logger.critical(out)
                         raise RuntimeError
-                    ecode, out = b4.git_run_command(gwt, ['checkout'], logstderr=True)
+                    ecode, out = b4.git_run_command(gwt, ['checkout', '-f'], logstderr=True)
                     if ecode > 0:
                         logger.critical('Error running checkout into sparse workdir')
                         logger.critical(out)
-- 
MST

Re: [PATCH 0/2] b4: sparse-checkout related fixes

[Michael S. Tsirkin]

On Mon, Oct 13, 2025 at 06:20:06PM -0400, Michael S. Tsirkin wrote:
> I encountered shazam test failures, diagnozing them I realized
> b4 misuses the sparse-checkout command.
> This patchset cleans this up.
> Pls review, thanks!

Hi Konstantin,
Just making sure sending this to tools@kernel.org is
the right thing. And do you want to be CC'd? Thanks!


> Michael S. Tsirkin (2):
>   test_shazam: clean worktree before git am
>   ez: cleanup sparse-checkout usage
> 
>  src/b4/__init__.py | 6 +++---
>  src/b4/ez.py       | 6 +++---
>  2 files changed, 6 insertions(+), 6 deletions(-)
> 
> -- 
> MST
> 

Re: [PATCH 0/2] b4: sparse-checkout related fixes

[Konstantin Ryabitsev]

On Wed, Oct 15, 2025 at 05:07:07PM -0400, Michael S. Tsirkin wrote:
> On Mon, Oct 13, 2025 at 06:20:06PM -0400, Michael S. Tsirkin wrote:
> > I encountered shazam test failures, diagnozing them I realized
> > b4 misuses the sparse-checkout command.
> > This patchset cleans this up.
> > Pls review, thanks!
> 
> Hi Konstantin,
> Just making sure sending this to tools@kernel.org is
> the right thing. And do you want to be CC'd? Thanks!

Nope, it's all good, I just haven't been able to review it yet.

-K

Re: [PATCH 0/2] b4: sparse-checkout related fixes

[Konstantin Ryabitsev]

On Mon, 13 Oct 2025 18:20:04 -0400, Michael S. Tsirkin wrote:
> I encountered shazam test failures, diagnozing them I realized
> b4 misuses the sparse-checkout command.
> This patchset cleans this up.
> Pls review, thanks!
> 
> Michael S. Tsirkin (2):
>   test_shazam: clean worktree before git am
>   ez: cleanup sparse-checkout usage
> 
> [...]

Applied, thanks!

[1/2] test_shazam: clean worktree before git am
      commit: 72af5e2f16d67610a018c08d264cd9c160cce8bf
[2/2] ez: cleanup sparse-checkout usage
      commit: 9e52ea82688a8ca37e6f59a86a723768c6044547

Best regards,
-- 
Konstantin Ryabitsev <konstantin@linuxfoundation.org>

Re: [PATCH 0/2] b4: sparse-checkout related fixes

[Konstantin Ryabitsev]

On Mon, 13 Oct 2025 18:20:04 -0400, Michael S. Tsirkin wrote:
> I encountered shazam test failures, diagnozing them I realized
> b4 misuses the sparse-checkout command.
> This patchset cleans this up.
> Pls review, thanks!
> 
> Michael S. Tsirkin (2):
>   test_shazam: clean worktree before git am
>   ez: cleanup sparse-checkout usage
> 
> [...]

Applied, thanks!

[1/2] test_shazam: clean worktree before git am
      commit: 72af5e2f16d67610a018c08d264cd9c160cce8bf
[2/2] ez: cleanup sparse-checkout usage
      commit: 9e52ea82688a8ca37e6f59a86a723768c6044547

Best regards,
-- 
Konstantin Ryabitsev <konstantin@linuxfoundation.org>

Re: [PATCH 0/2] b4: sparse-checkout related fixes

[Konstantin Ryabitsev]

On Wed, Oct 22, 2025 at 03:57:43PM -0400, Konstantin Ryabitsev wrote:
> [1/2] test_shazam: clean worktree before git am
>       commit: 72af5e2f16d67610a018c08d264cd9c160cce8bf
> [2/2] ez: cleanup sparse-checkout usage
>       commit: 9e52ea82688a8ca37e6f59a86a723768c6044547

Sometimes you find bugs in your own stuff. :)

Ignore the duplicate, please -- this is because I retrieved this patchset
again while testing fixes for "git am".

-K